1. Field of the Invention
The invention relates generally to cylinder liners for internal combustion engines, engine block assemblies including the cylinder liners, and methods of manufacturing the same.
2. Description of the Prior Art
Engines today are preferably designed to be smaller and lighter in order to condense packaging, reduce engine mass, and improve fuel economy. However, the smaller size can cause problems and concerns for finding places and positions for various components and machining. One of the areas of concern is the smaller interbore bridge area between the piston cylinder openings in the engine block. When cooling of the interbore bridges is necessary, drilled holes and/or saw slots can be machined into the bridge areas. Given the smaller bore spacing, and if liners are positioned in the cylinders, it can be difficult to machine the saw slots and/or drill the holes without contacting the cylinder liners and damaging the cutting tools. This can cause scrappage of the engine block and/or block line downtime.
Turning down the outside surface of the cylinder liners can create some additional space in the interbore bridge regions for slot and hole machining. However, this can result in poor thermal conductivity and large magnitudes of bore distortion due to the lack of physical or mechanical bonding of the cylinder liner to the engine block. These conditions are undesirable in these critical regions of the engine block.